diff --git a/src/ZodSchemaClass.ts b/src/ZodSchemaClass.ts
index db17a1c..07c0342 100644
--- a/src/ZodSchemaClass.ts
+++ b/src/ZodSchemaClass.ts
@@ -27,6 +27,8 @@ extends TraitExpressionBuilder<Superclass, Traits> {
     // }
 
     schema<
+        Superclass        extends AbstractClass<object> & { schema?: never, defaultValues?: never },
+
         SchemaT           extends z.ZodRawShape,
         SchemaUnknownKeys extends z.UnknownKeysParam,
         SchemaCatchall    extends z.ZodTypeAny,
@@ -34,7 +36,7 @@ extends TraitExpressionBuilder<Superclass, Traits> {
         Values            extends object,
         DefaultValues     extends Partial<Values>,
     >(
-        // this:           This,
+        this:           ZodSchemaClassBuilder<Superclass, Traits>,
         schema:         z.ZodObject<SchemaT, SchemaUnknownKeys, SchemaCatchall, Values, Values>,
         defaultValues:  DefaultValues,
     ) {